Prosthetic valves, such as prosthetic heart valves, are implanted in the body to replace a failing or diseased natural valve. Should the prosthetic valve begin to fail, it also may need to be replaced with another prosthetic valve. Surgically implanted, prosthetic heart valves, such as a prosthetic aortic valve, typically are replaced about every 15 years. The current method for replacing a surgically implanted, prosthetic heart valve involves open heart surgery wherein the patient's chest is opened and the existing prosthetic valve is removed and replaced with a new prosthetic valve. As can be appreciated, this is a traumatic and high risk procedure accompanied by substantial morbidity and mortality, and in some cases, cannot even be attempted due to the advanced age and/or medical condition of the patient.
Therefore, it would be preferable to replace a prosthetic heart valve with a percutaneously implanted valve that is delivered to the implantation site via the patient's vasculature and deployed within the previously implanted valve. However, because existing prosthetic heart valves can vary widely in size and shape, there are substantial difficulties associated with the development and validation of a percutaneously delivered replacement valve that is compatible with different types of existing prosthetic heart valves. More particularly, difficulties arise because a replacement valve that does not conform to the geometry of the previously implanted valve may not be able to adequately anchor to the previously implanted valve and/or form an effective seal with the previously implanted valve.